Safety flashers are well known effective warning devices which are used in conditions of reduced visibility and/or at night and have been employed in association with aircraft, emergency vehicles, on construction barricades and the like. Hazard lights, now adopted as standard equipment on wheeled conveyances for use when the conveyance is stalled or parked, demonstrate the advantage of coloured flashing lights used to alert traffic of potential obstructions.
The beneficial features of safety flashers and hazard lights have not been adopted in a classification of lights which may be referred to as consumer or personal portable lights and which are generally known as flashlights. The reasons are not clear. It is possible that the cost of commercial safety flashers and hazard lights is prohibitive to the general consumer. Perhaps, the availability of flashlights may have pre-empted the use of safety flashers by individual consumers. In any case, it is believed that a flashing light is preferred to a non-flashing light for pedestrian or bicyclist use because flashing lights are generally regarded as alerting or cautioning signals to which people respond rapidly. For similar reasons, it is preferred to use coloured lights as opposed to white lights.
As is well known, domestic flashlights are not normally used in a flashing mode to provide a flashing signal; rather, they are normally used in a continuous mode to selectively illuminate a particular area. Additionally, domestic or conventional flashlights normally utilize white light reflected through a clear lens. Thus, domestic flashlights do not provide the advantages of safety flashers and hazard lights.
Domestic flashlights may provide a flashing light by means of a momentary switch and some are known to provide a bi-metallic lamp and coloured lens in a secondary circuit. The latter has not been generally accepted in either method and this may be a result of the ineffective, inconvenient and somewhat unreliable nature of the first feature or the weight and expense of the battery necessary to power the bi-metallic lamp with its associated delayed response in the circuit. A further disadvantage of conventional flashlights is that they tend to be viewed from one direction only, that is, from a head on direction.